Incidentally, female chimps seem to live 25% longer than males—imagine human women lived until 90 while men died at 71.
Arithmetic error? both 71*1.25 and 71.5*1.25 to the nearest integer are 89, not 90. The error might (low-confidence, 10%) have been caused by calculating a 12.5% increase of 80 (exactly 90) and also dividing 80 by 1.125 (~71.1).
Well done, yes, I did exactly what you suggested! I figured that an average human lifespan was “around 80 years” and then multiplied and divided by 1.125 to get 80×1.125=90 and 80⁄1.125=71.111.
(And of course, you’re also right that this isn’t quite right since (1.125 − 1⁄1.125) / (1/1.125) = (1.125)²-1 = .2656 ≠ .25. This approximation works better for smaller percentages...)
Arithmetic error? both 71*1.25 and 71.5*1.25 to the nearest integer are 89, not 90. The error might (low-confidence, 10%) have been caused by calculating a 12.5% increase of 80 (exactly 90) and also dividing 80 by 1.125 (~71.1).
Well done, yes, I did exactly what you suggested! I figured that an average human lifespan was “around 80 years” and then multiplied and divided by 1.125 to get 80×1.125=90 and 80⁄1.125=71.111.
(And of course, you’re also right that this isn’t quite right since (1.125 − 1⁄1.125) / (1/1.125) = (1.125)²-1 = .2656 ≠ .25. This approximation works better for smaller percentages...)